To efficiently utilize the material of a workpiece, such as a metal plate, edges of the workpiece mounted on a cutting table of an automated cutting system must be identified. Conventionally, the process of identifying the edges of a workpiece is performed manually, for example, with one or a team of operators positioning the plasma arc torch over an edge of the plate and entering that position point into a computer numerical control (“CNC”) system. Several points are manually entered to define the edges of the workpiece, plate, or remnant to be cut. The CNC can then be used to orient a part program for processing the workpiece.
Other known techniques use an optical sensor to identify the edges of a workpiece. The optical sensor can be installed as a piece of additional equipment of an automated cutting system. Once installed, the optical sensor can be capable of detecting the edge of a workpiece.
Conventional methods of workpiece edge detection suffer from a number of shortcomings. The manual operator-based edge detection method is time-consuming and relies on visual feedback to identify the workpiece edge. The manual edge detection method can require multiple personnel and significant trial and error, in part because the distance between an operator's visual inspection of the plate edge and the operator inputs for the CNC system control can be great, especially for cutting tables having long lengths, for example, as long as 100 feet. This process is inefficient, expending unnecessary resources before the system can even make a cut. The potential for inaccuracies also creates a need to have an undesirably large scrap clearance at edges of a plate, detrimentally increasing the amount of waste remaining after conclusion of the cutting operation. Implementation of an optical sensor can be cost prohibitive and adds complexity to an automated cutting system, including additional equipment, controls, specialized setup requirements, and optical calibration and alignment. The use of an additional component can introduce an additional failure mode to an automated cutting system. Accordingly, there exists a need for an improved system or method for identifying edges or other features of a workpiece.